Bat structure in a baseball bat

ABSTRACT

To provide a bat structure that enables a batter to achieve a system of changing of the grip center position Gc of palm gripping by a bottom hand to Gc 1  of palm gripping by bottom hand and a half of upper hands, which leads to move the batting centroids Pc to Pc 1 . Also, the bat structure is also provided in which by adding a weight ΔM (10˜100 gr) to the bat head H of the bat having the grip structure of the kind referred to above, the batting energy at the sweet spot is improved to enhance the impact having the maximum batting effect together with change of the batting centroids Pc to Pc 1.

This application is a continuation-in-part application of U.S. patent application Ser. No. 15/507,409, and the specification and claims thereof are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a bat structure in a baseball bat, which is designed to enable a batter to practice an ideal batting by position control of a batting centroids Pc which is caused by changing the grip center Gc of palm gripping to Gc1. Especially, the present invention is to provide a bat structure that enables a batter to achieve a system of changing of the grip center position Gc of palm gripping just by a bottom hand to Gc1 of palm gripping by bottom hand and a half of upper hands, which leads to move the batting centroids Pc to Pc1 as shown in FIG. 14.

BACKGROUND ART

A grip of the bat used in baseball games is an important portion of the bat which assists a proper and good bat swing to be accomplished. In general, in the case of right handed players, they are used to grip the bat grip area with a second joint of one of their right-hand fingers positioned between the second joint of one of the left-hand fingers (bottom hand as they are so called) and the root of such finger. This way of gripping the baseball bat is generally considered the most orthodox way of gripping the baseball bat and, in this orthodox way of gripping, it is regarded proper if the respective backs of the right and left hands are held parallel to each other. The non-patent document 1 listed below addresses that according to the above discussed orthodox griping, the bat is held at the “top” position when the bat has been taken back, the bat swinging leads to align the line, drawn between the shoulder of the bottom hand to the arm, and the bat with the plane of swing towards a ball, such that the right angled relationship can be established between both hands and the bat to allow the swinging to be accomplished to put the bat out from the inside” along the bottom of the hand line. To impart both a strength and a controllability to the bat being then gripped, it is recommended to grip a lower region of the bat grip area with the palm of the bottom hand and, on the other hand, to bring the second joint of the finger of the top hand to a position between the second joint of the fingers of the bottom hand and the root of such finger with the top hand gripped by a finger grip.

The Giant patent document 1 referred to below suggests a grip structure designed to increase the grip strength during the swinging by utilizing the angle of inclination defined between the bat grip area of a substantially round sectional shape and with a knob-like grip end and by forming a gently curved support surface in a lower edge of the grip end so that the short palmar muscle and the abductor muscle of little finger may be supported. On the other hand, the Bruse patent document 2 referred to below suggests a grip portion for the bottom hand, which is of a non-circular sectional shape, and formation of an asymmetrically flared portion in a region above the non-circular sectioned grip portion so as to allow the bottom hand to achieve the palm grip.

PRIOR ART LITERATURE Patent Documents

-   Patent Document 1: U.S. Pat. No. 7,744,497 -   Patent Document 2: U.S. Pat. No. 7,878,930

Non-Patent Documents

-   Non-patent Document 1: Ken Maeda, “(Book of Batting     Mechanism)(Theory), published by (Baseball Magazine Co., Ltd.)

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

It has, however, been found that while, in the former case the design is such that the grip area of the bat represents a virtually circular cross section to allow an inclined portion of the bat, which lies intermediate between the grip area and the knob-shaped grip end, and a gently curved support surface, which lies at a lower edge of the grip end for supporting the short palmar muscle and the abductor muscle of little finger to grip with a palm of the bottom hand, difficulty is encountered in maintaining such particular grip. On the other hand, if the grip area for the bottom hand is designed to represent a non-circular cross section and a lower region of the bat from the bat end is inclined to flare outwardly to suit to the palmar grip with the bottom hand such as suggested in the latter case, it has been found that because of the non-circular cross sectional shape represented by the grip area, but also because top and bottom distances relative to the longitudinal center line of the bat become asymmetrical to each other due to the flared inclination of the cross sectional shape, making the bat by rotating a wooden bolt about the longitudinal axis thereof becomes extremely difficult to produce the intended bat.

In view of the foregoing, the present invention has for its object to provide a bat structure that can be relatively easily manufactured and that can enlighten the batter about the downswing.

Another important object of the present invention is to provide a bat structure which makes it possible to accomplish a high angular speed swing to take out the bat from inside and to bring the center of gravity close to the batting centroid, thereby enabling the batter to have the maximum batting effect.

Means for Solving the Problems

At the “top” position during the take-back in batting practice, in order to match the line, drawn from the shoulder to the arm of the bottom hand and the bat with the plane of swing oriented towards the pitch, the bat grip should create three right angled relationships between both hands and between each of the arms and the bat and, along the line of the bottom hand in dependence on those three right angled relationships so that the swing “to put the bat out from inside” can be accomplished. The first necessity is to provide the grip structure effective to maintain the right angled relationship between the forearm of the bottom hand and the longitudinal axis of the bat while the bat is gripped with the bottom hand under the palmar grip. But it has been found that, in order to facilitate the grip structure referred to above, in the bat grip, although the sectional shape of at least the bottom grip ranging from the grip end to the center of grip must be a generally oval shape and, when the oval sectioned grip portion is gripped in the palm grip, the locking structure, which turns to urge the bottom hand, then gripping the oval sectioned grip portion with the bottom hand under the palmar grip in a direction towards the thumb side about the hand wrist is made so as to incline the grip end relative to the longitudinal axis of the bat grip. Furthermore, to maintain the locking function thereof, the little finger tip and/or the palm end below the little finger third joint will not drop out from the grip end, a new grip end of a Japanese Otafuku shape (a generally trochoidal shape), in which at least one side face of the grip end, preferably opposite side faces thereof, protrude laterally outwardly, has been also found to be necessary. Therefore, according to the preferred embodiment of the present invention,

there is provided a bat structure which includes a bat head (H), a bat barrel portion (B), a bat throat portion (T), a bat grip portion (G) and a grip end (E), and the bat whole length is less than 86 cm according to the rule and the length of the bat grip portion is 25 to 35% of the bat whole length wherein;

1) the grip portion (G) comprises 3 parts extending from the grip end (E) to the bat throat portion (T) and a first part close to the grip end (E) has about half length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally vertical oval shape all over suited for gripping with palms of a bottom hand and a upper hand, a second part has less than one sixth length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is gradually changed from a generally vertical oval shape to a generally circle shape suited for gripping with thumb and index fingers of the upper hand and a third part close to the throat portion (T) has a remaining length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally circle shape. Further, according to the baseball rule, in the bat structure the bat whole length for adult can be chosen from 82 cm to 86 cm while the bat whole length for boy can be chosen from 68 cm to 80 cm, and the length of the first part in the grip portion (G) is set from 11 cm to 14.5 cm. Furthermore, the bat structure should be, characterized in that:

2) the grip end (E) is inclined forwards at an angle within a range of 20 to 30 degrees relative to a plane perpendicular to the longitudinal axis of the bat, and has a lock structure capable of turning about the hand wrist of the bottom hand to urge towards a thumb side or should be characterized in that:

3) the grip end includes a top side, a bottom side which being opposite to the top side, a first right side and a second left side being opposite to the first right side, and projects laterally outwardly at the first right side or the second left side of an end inclined face over the generally oval section of the grip portion to form a bulge portion having a step portion between the grip end and the grip portion (G) for engaging with the little finger tip or the palm edge adjacent to the little finger third joint of the bottom hand in a manner to prevent the bottom hand edge from slipping out from the grp end during the swinging. According to the preferred embodiment, the bat structure should be characterized in that:

4) a weight of the bat head H can be increased by adding a weight ΔM (10˜100 gr) to move the gravity center (C) of the bat from the original position toward the batting centroids Pc.

Effects of the Invention

According to the present invention, thanks to the oval sectional shape of the grip portion, the palmar grip of the bottom hand is realized and, in the case of the right-hand batter, it can be locked by pressing the back of the bottom hand clockwise by the locking structure. Also, so that the locking of the bottom hand during the swinging will not be released, the side face of the grip end in the vicinity of the locking mechanism is rendered to bulge outwardly to represent the Japanese Otafuku shape and the possible drop-out of the little finger tip or the palmar end portion below the little finger third joint of the palmar grip from the grip end is avoided to maintain the palmar grip of the bottom hand during the swinging and, therefore, gripping of the bottom hand maintains the right-angled relationship between the forearm and the longitudinal axis of the bat and, as a result that a proper swinging “to put the bat out from inside” is achieved, an action “to swing the bat as if hitting the grip” can be induced to thereby increase the angular velocity of the bat swinging.

In the Giant's U.S. Pat. No. 7,744,497 referred to above, an inclined angle is provided between the grip portion of a substantially circular sectional shape and the knob-like grip end, and a gradually curved support surface for supporting the short palmar muscle and little finger abductor muscle of the bottom grip is formed at a lower edge of the grip end to thereby increase the gripping strength during the swinging, but the present invention departs from the teachings of the Giant US patent in respect of such an excellent function that, even though such a support surface is employed nowhere in the bat designed in accordance with the present invention and the grip portion of the bottom hand is rendered to have the oval sectioned shape and, at the same time the palmar grip is maintained during the swinging with the Japanese Otafulu shaped inclined grip end. On the other hand, the Bruse U.S. Pat. No. 7,878,930 discloses formation of an asymmetrical flared portion as a grip portion in an upper portion of the grip portion of the non-circular sectional shape so that the palmar grip can be made with the bottom hand, and, since the distance up and down from the center axial line (longitudinal axis) of the bat is asymmetrical, the manufacture of the bat is difficult, but in the practice of the present invention, the axial line (longitudinal axis) of the grip portion is matched with the bat axial line (longitudinal axis of the bat) and the bottom hand is locked with the locking mechanism in the inclined end face at the grip end. Also, although the bottom hand is apt to separate away from the grip end if only a portion of the grip end that contacts the little finger second joint is merely inclined to flare forwardly, the present invention is such that of the non-circular sections, an oval section that can be relatively easily manufactured is selected and the above discussed problem is resolved by somewhat bulging the lateral face outwardly to enable the grip end to represent the Japanese Otafuku shape, wherefore reinforcement can be made to expand the locking function of the bottom hand to thereby avoid the separation during the swinging.

Also, in the present invention, by rendering the section of not only a portion ranging from the grip end to the grip center, but also a grip portion of three fingers of the upper hand, including at least the middle finger to the little finger in a direction from the grip center to the bat head, which lies perpendicular to the bat longitudinal axis, to be a generally oval shape, not only the bottom hand, but also the grip portion of the three fingers of the upper hand, including the middle finger to the little finger in a direction from the grip center to the bad head is rendered to be a half palmar grip excellent in controllability to enable a strong hitting to be accomplished and, therefore, the feeling similar to that obtained when the downswing is performed can be given particularly in batting in the soft ball game.

Also, where the palmar grip is preferred, the semiperimetric portion of the grip portion that is gripped by the palm of the hand does not only form the above described locking mechanism in the upper portion, but also it is recommended to form the inclined region at least in the intermediate portion and in the vicinity thereof which increases the coefficient of friction of the grip. On the other hand, even in the upper region of the grip portion ranging from the grip center to the throat portion, it is recommended to form the grip frictional coefficient increasing portion, to permit the bottom hand to grip the grip lower portion under the palmar grip and to cause the upper hand to grip the grip upper portion with the controllable palmar grip.

Considering this action mechanically in connection with the batting, as shown in FIG. 10, the bat has the barrel portion B of the largest uniform diameter from the head H at the tip end thereof and, also, has the grip portion G, with which the bat is gripped and which grip portion G extends from the barrel portion B through the throat portion T having its diameter progressively decreasing, and generally terminates at the grip end E. And, considering that the batting is an elastic collision, it is a proposition of batting that the bat is gripped at the grip portion G, is drawn to swing at the maximum angular velocity ω, is applied the kinetic energy F=1ω which is expressed by the product of the angular velocity ω and the inertia moment I in the center of gravity G that is spaced a distance a from the center Gc of gripping, and the kinetic energy given by this maximum angular velocity is struck at the sweet point, located in the vicinity of the bating centroid P of the bat, and is then transmitted to the ball. Also, according to the second preferred embodiment of the present invention, the bat structure which utilizes the above discussed grip structure and, based on the above discussed proportion, the bat swinging can be accomplished at the maximum angular velocity ω the player can exert, the pitch can be struck at the sweet spot in the bat while the maximum inertia moment I is applied to the center of gravity C of the bat.

In other words, firstly, since in order to accomplish the bat swinging at the maximum angular velocity ω, the three right angled relationships for “putting the bat outwardly from inside” are formed when the grip structure capable of accomplishing the palmar grip of at least the bottom hand is used to thereby accomplish the swinging “to swing the bat as if striking the grip”. For the “swinging of the bat as if striking the grip”, the grip structure is needed in which the right-hand batter should grip and lock, under the palmar grip, with the back of the left hand oriented upwardly during the swinging, and exercise to urge the bat incident to rotation of the hip below such grip to thereby complete it (FIG. 13B). And, secondly, the bat swinging at the maximum angular velocity applies the inertia moment about the center of gravity and the product of the inertia moment and the bat swinging angular velocity ω is applied in the form of the kinetic energy F to the ball and, thus, the batting energies for the ball is assured and the elastic collision with this ball takes place at the sweet spot. The sweet spot referred to above is the point at which the high coefficient of restitution (FIG. 10) and the batting centroid referred to above is the immovable point at which, when the bat impinges upon the ball, it leads that the translational motion of the center of gravity of bat and the rotatory motion about the center of gravity are counterbalanced with each other, but consequent upon the availability of the batting energy most effective to the batting at the sweet spot at which the high coefficient of restitution can be obtained, and as a result that the batting is made at the first maximum angular velocity and at the second maximum batting energy, the maximized batting effect can be obtained.

Accordingly, a second preferred embodiment of the present invention is based on the above discussed finding and, therefore, in accordance with this aspect of the present invention, there is also provided a bat grip structure which includes a bat head H, a bat barrel portion B, a bat throat portion T, a bat grip portion G and a grip end E, characterized by the provision of 1) a gravitational center position changing structure for displaying the original position of a bat center of gravity C, which lies at the bat barrel portion B, in a batting centroid Pc direction by adding an additional weight ΔM to the bat head, the grip portion has a sectional shape perpendicular to the longitudinal axis of the bat, which shape is represented by a generally oval shape suited for gripping with a palm, in which when the grip center Gc is moved to Gc1 by changing a palm gripping of the bottom hand to a palm gripping of the bottom hand and a half of the upper hand, the batting centroid Pc is adjustable to Pc1 while securing the palm grip of the bottom hand is secured, and in that 2) the grip end is inclined forwards at an angle within the range of 20 to 30 degree relative to a plane perpendicular to the longitudinal axis of the bat, and has a lock structure capable of turning about the hand wrist of the bottom hand to urge towards a thumb side and 3) the grip end bulges laterally outwardly of an end inclined face over the oval section of the grip portion G, an outwardly bulged portion of a Japanese Otafuku shape engageable with the little finger tip and/or a palm portion adjacent the little finger third joint of the bottom hand is formed therein and the maximum moment I ω imposed on the center of gravity that is obtained at the maximum angular velocity ω brought about by the grip structure has a function of transmitting the batting centroid Pc˜Pc1.

According to the present invention, when by the first effect of a weight ΔM added to the bat head H, the bat center of gravity C, which lies in the bat barrel portion B, is moved from the original position in a direction towards the batting centroid P, the kinetic energy F applied to the pitch at the sweet spot located in the vicinity of the batting centroid is maximized. And, also, by the second effect of the locking structure formed from the grip end E to the grip G, the back of the bottom hand opposite to the dominant arm is locked and is oriented upwardly to invite the batting impact to make it possible to realize the batting swing as if “swing the bat as if striking the grip” and thereby apply the maximum angular velocity to the bat swinging. By the cumulative effects described above, the maximum batting efficiency can be obtained. Although the weight ΔM to be added to the bat head has to be chosen depending on the total weight of the bat, a range of 10 to 100 gr is preferred. Also, regardless of the gripping position, the bat structure is provided with a grip structure which is designed to allow at least the bottom hand to grip under the palmar grip and thereby provide the maximum angular velocity. Further the bat structure can be provided with a changeable system of the grip center position Gc to Gc1 to move the batting centroids Pc to Pc1, while the bat structure is provided with a changeable system for the bat center of gravity C from the original position toward the batting centroid Pc by the effect of the weight ΔM added to the bat head H, thereby enabling each batter to select a proper batting method applicable or suitable to each batter.

The grip structure of the present invention is preferably formed in a wooden bat, but it may be formed in metal or a general material which is not an arbitrarily chosen wood.

A portion at which the coefficient of friction of the bottom hand is preferably around half of the entire periphery of a lower half portion of the grip portion, but it is recommended to form at least an intermediate portion of the grip portion and in the vicinity thereof in a region ranging from the gripping center to the grip end. The length of that portion at which the coefficient of friction of the grip portion is increased has to be in accord with the rule (pine tar rule) set forth in the rule book, available from the United State Major League Baseball Committee and stipulated in connection with the length over which pine tar.

Also, if 1), when the palm of the bottom hand is in contact with a portion of the grip portion G ranging from the grip end to the bat throat portion T, the sectional shape perpendicular of the grip portion ranging from the palm of the bottom hand to the middle finger of the upper hand that lies perpendicular to the longitudinal axis of the bat is represented by a generally oval shape suited for gripping by the palm, and an inclined portion is formed in a direction upwardly of the bat over the middle finger of the upper grip to change at least the grip portion oval sectional shape to a circular sectional shape of the bat throat portion to thereby form a double stepped grip, and, even though the grip center Gc is moved to Gc1, selection of one of a half palmar grip, in which, while the palmar grip for the bottom hand is secured, the little finger and the thumb finger in the grip is released, and a finger grip is possible and the batting adjustment appropriate to any batter is possible incident to displacement Δa of the center of gravity referred to above and the displacement of the batting centroid from Pc to Pc1 (See FIG. 14).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a grip structure designed in accordance with a preferred embodiment of the prior art, which includes a palmar surface of the bottom hand in a grip area of an oval sectional shape, with a grip end surface lying at an angle within the range of 20 to 30 degrees relative to a plane perpendicular to the longitudinal axis of the bat, and a lock structure defined at the boundary between the grip area and the grip end;

FIG. 2 is a perspective view showing the grip area being gripped, in which the lock structure is represented by a Japanese Otafuku shape (virtually trochoidal shape) that form a bulged portion swelling outwardly along a grip end inclined surface, which serves to avoid drop-out of the tip of little finger and the third joint of little finger and also a palmar end situated therebelow;

FIG. 3A is a diagram showing the basic shape, as viewed from diagonally rearward, in which three right angles are depicted at top;

FIG. 3B is a diagram showing the basic shape, as viewed from rearward, in which three right angles are depicted at top;

FIGS. 4A-4D are explanatory diagrams showing the sequence of batting in which the distance between the bat and a batter's shoulder and also the right angular relationship between the bottom hand and the bat do not change from the condition shown in FIGS. 3A and 3B;

FIGS. 5A-5C illustrate a first modified form of the grip structure designed in accordance with the present invention, in which FIG. 5A illustrates an enlarged diagram of the grip end portion of the bat, FIG. 5B illustrates a side view thereof, and FIG. 5C illustrate respective cross sectional views taken along the lines A-A, B-B, C-C and D-D, respectively; which has the grip area of the oval sectional shape, an inclined Otafuku shaped grip end that is inclined from the grip end for the bottom hand for contact with the little finger tip and the little finger second joint, and the lock structure disposed at the boundary between the grip are and the grip end for locking the bottom hand;

FIGS. 6A-6C illustrate a second modified form of the grip structure designed in accordance with the present invention, in which FIG. 6A illustrates an enlarged diagram of the grip end portion of the bat, FIG. 6B illustrates a side view thereof, and FIG. 6C illustrate respective cross sectional views taken along the lines A-A, B-B, C-C and D-D, respectively; which has the grip area of the oval sectional shape, an inclined Otafuku shaped grip end that is inclined from the grip end for the bottom hand for contact with the little finger tip and the little finger second joint and also a palmar end below the little finger third joint, and the lock structure disposed at the boundary between the grip are and the grip end for locking the bottom hand;

FIGS. 7A and 7B illustrate a third modified form of the grip structure designed in accordance with the present invention, in which FIG. 7A shows the bat in its entirety, the locking mechanism being formed at the boundary between the inclined Otafuku shaped grip end that is inclined for contact with the little finger tip and the little finger second joint and the palmar end below the little finger third joint, in which lower three fourths (¾) of the grip area is formed to represent an oval sectional shape and forms a palm grip for contact with the oblong oval shape varying to the circular sectional shape in a direction towards a sloped portion, and FIG. 7B illustrates a longitudinal sectional view thereof;

FIG. 8A illustrates an enlarged diagram of the grip end portion of the bat shown in FIGS. 7A and 7B, FIG. 8B illustrates a side view thereof, and FIG. 8C illustrate respective cross sectional views taken along the lines A-A, B-B, C-C and D-D, respectively;

FIG. 9 is a perspective view showing a third modified form of the present invention, showing a end manner in which the grip area is grasped by the bottom hand and the top hand and in which, although the bottom hand assumes a palmar grip, the top hand assumes a semi-palmar grip with the thumb and the index finger opened, to enable a firm grip to be accomplished during the down swinging and for women's soft ball games.

FIG. 10 is a perspective view showing only the grip portion of the bat designed in accordance with the third modification of the present invention, in which the grip end is of a design in which every lower end portion thereof coincides substantially with the grip contour, which are shown as an angle of 20, 25 or 30 degree respectively relative to the vertical line lying perpendicular to the longitudinal axis of the bat while outer and left and right ends thereof are somewhat swelled outwardly from the perimeter of the grip portion of an oval sectional shape along the inclined surface in the grip end. Thereby, the grip upper end forms the locking structure for the bottom hand while the left and right ends of the grip end are so shaped as to avoid the drop-out of the little finger tip and a palmer end below the little finger third joint, thereby completing the structure for maintaining the bottom hand in a locked condition.

FIG. 11 is an explanatory diagram to show the function of the conventional bat.

FIG. 12A is a perspective view of the bat structure together with a top end and a bottom end view according to the prior art and FIG. 12B is a longitudinal sectional view.

FIG. 13A is a perspective view showing a manner of the grip being grasped according to the present invention.

FIG. 13B is a cross sectional view taken along the line B-B in FIG. 13A.

FIG. 13C is explanatory diagrams showing respective conditions of the bottom hand and the physical angle that are exhibited at the time of impact at the inside (1), the middle (2) and the outside (3) of a right-handed batter then gripping the bat in the manner shown in FIG. 13A.

FIG. 14 is an explanatory diagram showing displacement of the batting centroid caused by displacement of the center of gravity, brought about by addition of a weight to the head of the bat and by displacement of the center of grip.

FIG. 15(A) is a grip structure of the prior art shown in FIG. 12A, FIG. 15(B) is a grip structure of the present invention shown in FIGS. 5A-C, 6A-C, 7A, 7B, and 8A-C, and FIG. 15(C) is a comparative drawing of FIGS. 15(A) and 15(B).

BEST MODES FOR CARRYING OUT THE INVENTION First Preferred Embodiment 1

Hereinafter a first preferred embodiment of the present invention will be discussed.

Referring to FIG. 1, there is shown a side view of a baseball bat in its entirety, which bat includes a bat head H, a bat barrel portion B, a bat throat portion, a bat grip portion G and a grip end E. The bat in its entirety is made of wood and, although an end face of the bat head represents a circular shape, a grip end face represents a Japanese Otafuku shape (a generally trochoidal shape) that is generally similar to the oval shape having its opposite sides bulged outwardly, and is so formed as to have the shape changing from an oval section at the grip area to an exact circle at the throat area on one side of the center of the bat grip area opposite to the bat barrel B. According to the baseball rule, the bat whole length is less than 86 cm which is almost equally divided by the bat barrel portion (B), the bat throat portion (T) and the bat grip portion (G) and the length of the bat grip portion is 25 to 35%, preferably 28 to 33% of the bat whole length, so the bat whole length for adult can be usually chosen from 82 cm to 86 cm while the bat whole length for boy can be usually chosen from 68 cm to 80 cm, and the length of the first part in the grip portion (G) is set from 11 cm to 14.5 cm.

In the present invention, the bat structure is provided with 1) the grip portion (G) comprises 3 parts extending from the grip end (E) to the bat throat portion (T) and a first part close to the grip end (E) has about half length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally vertical oval shape all over suited for gripping with palms of a bottom hand and a upper hand, a second part has less than one sixth length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is gradually changed from a generally vertical oval shape to a generally circle shape suited for gripping with thumb and index fingers of the upper hand and a third part close to the throat portion (T) has a remaining length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally circle shape. According to the preferred embodiment of the present invention, the bat structure enables a batter to achieve a system of changing of the grip center position Gc of palm gripping by a bottom hand to Gc1 of palm gripping by bottom hand and a half of upper hands, which leads to move the batting centroids Pc to Pc1.

When a predetermined weight ΔM is added to the bat head H, the center of gravity C of the bat is displaced from the original position, which lies at the bat barrel B, by a quantity Δa in a direction towards the batting centroid P, and, therefore, the kinetic energy applied to the center of gravity increases. The bat structure is also provided in which by adding a weight ΔM (10˜100 gr) to the bat head H of the bat having the grip structure of the kind referred to above, the batting energy at the sweet spot is improved to enhance the impact having the maximum batting effect together with change of the batting centroids Pc to Pc1.

On the other hand, the barrel extends to the grip area G through the throat area T, with a generally oval shaped section represented over to the grip end E and, also, with a curved angle α being formed on a grip surface on an outside with respect to a center axial line that extends in the lengthwise direction, thereby completing a locking structure R. As a result that this locking portion R causes a left hand grip (bottom hand) of the right handed batter from a little finger side to a thumb side, the left hand wrist is urged counterclockwise to press, as shown by the arrow in FIG. 2, to keep the forearm of the bottom hand and the bat at a right angled relationship so that return of the back of the batter's left hand can be suppressed during the bat swinging and, also, bending of an elbow of the left hand is suppressed during the impact. Also, at a semiperimetric portion of the grip area then grasped by the palm of the bottom hand, the gripping coefficient of friction is increased. On the other hand, if in an upper region of the grip area ranging from the grip center to the throat area the coefficient of friction of that region is so increased as to bring the second joint of a finger of the top hand in between the second joints of fingers of the bottom hand and the roots of the fingers thereof, the top hand grasps the bat grip area under the finger grip (See FIG. 13A) so that the back of the bottom hand and the back of the top hand come to be parallel to each other. This is a condition in which in order to match the right angled relationship between the forearm of the bottom hand and the forearm of the top hand with the plane of swinging oriented towards a ball along a line from the shoulder to the arm and bat, the bat gripping creates three right angled relationships (1) between both arms, (2) between one of the arms and the bat and (3) between the other of the arms and the bat, respectively, so as that those three right angled relationship can be utilized to accomplish a sort of swing “to put the bat out from inside” along the line of the bottom hand.

The three right angles referred to above includes (1) the first right angle (FIG. 3A) between the forearm of the bottom hand and the bat (FIG. 3A), (2) the second right angle between the forearm of the bottom hand and the forearm of the top hand (FIG. 3A), and (3) the third right angle between the forearm of the top hand and the bat (FIG. 3B). Particularly, when the bat is in the top position, creating of the substantially right angled relationship between the forearm of the bottom hand and the bat, has extremely important implications and that is why the bat shown in (A) to (D) of FIG. 4 is so close towards the shoulder tip (acromion) that no change between it and the shoulder tip happens totally and a substantially right angled grip is kept and rather rotating power in most conditions is drawn thereby. Accordingly, putting the batr out from inside can be accomplished. In contrast thereto, if the angle between the bottom hand and the bat is obtuse when the bat is held in “top”, that is, the forearm of the bottom hand and the bat cooperate to form the obtuse angle when the bat is held in “top”, even though the length of time from the start of bat swinging to impact will become small, the bat head is apt to open on the side of a catcher from the beginning and, therefore, a sufficient distance of acceleration to the impact cannot be secured with the speed of movement of the bat head during the impact consequently failing to increase and, since the head is opened from the beginning, the bat head will quickly return under the outside pitch, constituting a cause of trick swinging. Accordingly, to maintain the substantially right angled relationship of the angle between the forearm of the bottom hand and the bat at the time the bat is held top, it will readily be seen that gripping a grip lower region with the bottom hand under the palmar grip is important.

Then, the right angle delimited between the forearm of the bottom hand and the forearm of the top hand controls both the rotation of the upper body and the respective movements of those arms which occur during the batting action and thus changes with the rotatory movement of the upper body brought about by the scapular movement, rather than being moved accompanied by the movements of the forearms. Accordingly, movement of both forearms while intersecting at right angles to each other results in the movement of the upper body at the time of start of swinging to draw the bat by the rotatory action along the line of the bottom hand without changing the distance from acromion to acromion (FIGS. 4B and C), thereby creating the behavior “to put the bat out from inside”. The right angle between the forearm of the bottom hand and the forearm of the top hand brings about the behavior “to put the bat out from inside”, in which the line ranging from the shoulder to arm of the bottom hand and to the bat can be matched with the plane of swinging the hand back of the bottom hand becomes parallel to the hand back of the top hand, when. while the palmar grip is realized on the bottom hand, the bat grip area is gripped by the top hand under the palmar grip or finger grip so that the second joint of fingers of the top hand may come in between the second joint of the fingers and the root of the fingers of the bottom hand

The grip structure in the bat referred to above is such as to have a shape varying from the grip end to the grip area, with the oval shape varying gradually to the circular shape, and, in the case of the oval shape, a top peripheral edge forms an inclined portion, but a region from a top peripheral edge to a lower peripheral portion of the grip end is flared wherefore a little finger side and a palmar side of the bottom hand is easy to be slipped. Accordingly, according to a first modification of the present invention, an intermediate area of the grip end is formed as a curved step portion to follow the contour of the little finger to improve the locking mechanism so that the palm of the bottom hand may not fall off from the grip end. FIGS. 5A-5C illustrate the grip structure designed for this purpose. FIG. 5A illustrates an end view showing an end face of the grip end, in which a portion of the grip end ranging from the top peripheral edge to an intermediate area of the semicircular bottom hand side is bulged outwardly and then curved to define a locking structure. This condition is best shown in the end view of FIG. 5A and the cross section view of FIG. 5C which is taken along the line A-A. In other words, in the end view of FIG. 5A, it represents a condition approximating to a Japanese Otafuku shaped oval sectional shape, and, as comparison with the following sectional view taken along the line A-A, a first curved step portion is formed in the top peripheral edge that may contact the second joint of the bottom hand so that the wrist is somewhat cocked having been turned counterclockwise. A zone from an upper peripheral edge to an intermediate peripheral edge is bulged outwardly and an inclined step portion is formed from the end towards the grip and thereby the back of the bottom hand is turned counterclockwise from a little finger side to a thumb finger side. Accordingly, the little finger side of the bottom hand can grip firmly under a power grip without falling off from the grip end and the forearm of the bottom hand comes to be maintained at right angles to the longitudinal axis of the bat.

FIGS. 6A-6C illustrate an improvement in and over the modification shown in and described with reference to FIGS. 5A-5C, which is so designed as to prevent the drop-out from the grip end on the palmar side of the bottom hand then under the power grip and as to maintain the power grip by the bottom hand. In other words, according to the second modification now under discussion, a peripheral portion at the vicinity of the grip end is bulged not only in an upper portion, but also in the both intermediate peripheral edges along a contact portion for the little finger tip and a contact portion for the lower palm of the little finger third joint to thereby prevent the drop-out of the palmar end of the bottom hand and the little finger side from the grip end to thereby increase the gripping force. The bat having the above described structure is shown in FIGS. 6A-6C. FIG. 6A illustrates an end view showing the end face of the grip end having the locking structure formed therein while an area ranging from the upper peripheral edge of the semi-perimeter on the bottom hand to the intermediate peripheral edge is curved down in a direction towards the grip area. This condition is shown in the end view of the end face shown in FIG. 6A and the cross section taken along the line A-A in FIG. 6C. In other words, in the end view of FIG. 6A, a condition is shown which approximates to the generally trochoidal (Japanese Otafuku shaped) sectional shape and, as comparison with the cross-sectional diagram taken along the line A-A, a first curved portion is formed in an upper peripheral edge on which the second joint area of the bottom hand rests with the wrist being locked having been somewhat cocked counterclockwise. In FIGS. 6A-6C, not only the area ranging from the upper peripheral edge to the little finger tip, but also the opposite intermediate peripheral edge of the palmar end below the little finger third joint, are formed with an inclined step portion extending from the grip end to the grip area and, thus, the back of the bottom hand is locked having been somewhat lifted counterclockwise from the little finger side towards the thrum side. Accordingly, the palmar side of the bottom hand can be gripped under the power grip firmly without falling out from the grip end and the forearm of the bottom hand can be maintained at right angles to the longitudinal axis of the bat.

As can readily be understand from the description made with reference to FIGS. 3A and 3B and FIGS. 4A to D, it is clear that (1) the first necessary task is to enable gripping in which the angle between the forearm of the bottom hand and the bat to be substantially right angles to each other at the time of the top position under the palmar grip with the bottom hand, and, (2) secondly, it is important to grip the bat grip area under the palmar grip or the finger grip with the top hand so that the finger second joint of the top hand can be brought in between the finger second joint and the finger root against the palmar grip of the bottom hand so that the forearm of the bottom hand and the forearm of the top hand may be right angled relative to each other. One of the objects of the present invention is to provide the grip structure effective to accomplish such a gripping as described above and is of a grip structure having, firstly, a region effective to increase the coefficient of friction necessary to accomplish such gripping as discussed above and, secondly, the gripping is accomplished under the right-angled relationship between the bottom grip and the bat.

The grip structure shown in FIGS. 7A, 7B, and 9 is provided with a bat structure which includes a bat head (H), a bat barrel portion (B), a bat throat portion (T), a bat grip portion (G) and a grip end (E), and the bat whole length is almost equally divided by the bat barrel portion (B), the bat throat portion (T) and the bat grip portion (G) wherein 1) the grip portion (G) comprises 3 parts extending from the grip end (E) to the bat throat portion (T) and a first part close to the grip end (E) has about half length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally vertical oval shape all over suited for gripping with palms of a bottom hand and a upper hand, a second part has about one sixth length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is gradually changed from a generally vertical oval shape to a generally circle shape suited for gripping with thumb and index fingers of the upper hand and a third part close to the throat portion (T) has about one third length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally circle shape. In the bat structure, it is general that the bat whole length for adult can be chosen from 83 cm to 85 cm while the bat whole length for boy can be chosen from 68 cm to 80 cm, and the length of the first part in the grip portion (G) is set from 11 cm to 14 cm. Therefore, especially in the bat grip area, the bottom hand grip ranging at least from the grip end to the grip center has a generally oval sectional shape in a plane perpendicular to the bat longitudinal axis; a grip portion for the top hand ranging at least from the middle finger to the little finger is rendered to represent a generally oval sectional shape in the plane perpendicular to the bat longitudinal axis; and a region transiting therefrom to the throat area includes the inclined area in which the oval sectional shape is transmitted to the circular section represented by the throat area. This lies in the bat grip structure of the type in which (1) the palm of the bottom hand is engaged with the grip end under the palmar grip and, on the other hand, (2) the middle finger to the little finger of the top hand is gripped to achieve a controllable palmar grip, and (3) the bottom hand is displaced in a direction towards the bat head under the palmar grip while the top hand is also displaced to grip the bat from the inclined portion. With the bottom hand and the top hand gripped under the palmar grip, downswing can be readily exercised, the grip suited for use in the women's soft ball game can be realized; selection of the bottom grip to grip under the palmar grip and the top hand to grip under the finger grip can be made; and thereby the batting centroid can be changed from Pc to Pct by displacing the grip center from Gc to Gc1 (FIG. 14).

The locking structure according to this embodiment now under discussion is formed (1) by causing either an upper end of the grip end to follow the finger pulp, (2) followed by somewhat bulging the little finger tip side of the grip end so that the region from the upper end of the grip end to both opposite ends thereof may brought into contact with the grip end, or (3) the little finger tip and the palmar peripheral end below the little finger of the grip end and so that the little finger tip of the bottom hand and the palmar end below the little finger may be brought into contact with the grip end. For this reason, the grip end represents the Japanese Otafuku shape with each corner portion inclined inwardly from the grip end so that the second joint of the bottom hand as well as the little finger tip side and the palmar end side can be reinforced to avoid the bottom hand slip-out from the grip end. It is to be noted that the lower end of the grip end is not necessarily bulged outwardly, but if the end grip is so shaped as to have an angle option of taking 20, 25 or 30 degree relative to the vertical line (FIG. 10), the locking strength of the grip can be increased.

Also, the region operable to increase of the coefficient of friction in the grip area is formed in at least an intermediate portion and in the vicinity thereof of the semicircular portion of the bottom grip portion that is grasped by the palm of the bottom hand so that gripping of the grip lower region (bottom) can be facilitated under the palmar grip of the bottom hand. With respect to the top hand, the region operable to increase the coefficient of friction in the grip area may be formed in at least an intermediate portion and in the vicinity thereof of the semicircular portion of the grip that is gripped by the palm corresponding to the middle finger, the third finger and the little finger so that gripping of the grip upper region (bottom) can be facilitated under the palmar grip of the top hand.

Second Preferred Embodiment

Hereinafter, a second preferred embodiment of the present invention will be discussed in detail.

FIG. 11 is a side view showing the baseball bat in its entirety, which includes a bat head H, a bat barrel portion B, a bat throat portion T, a bat grip portion G and a grip end E.

The bat in its entirety is made of wood and, one of ten adjustment cap type heads M is added to the bat head H of a standard weight so that the weight added to the bat head may be adjusted to a value, for example within the range of 10 to 100 grams. Although the end face of the bad head is circular, the grip end face is non-circular such as, for example, oval or egg-shaped.

Mechanical Analysis of the Batting on the Bat Structure

A predetermined weight ΔM is added to the bat head H. Thereby, the center of gravity C of the bat, which lies in the bat barrel portion, is displaced a distance Δa from the original position towards the batting centroid P (See FIG. 14). In contrast thereto, the batting centroid P does not virtually displace and, hence, the position of the sweet spot of the bat, which is located at a position adjacent the batting centroid with respect to the center of gravity C does not displace correspondingly. Therefore, since the kinetic energy F applied to the center of gravity C is increased by the distance Δa from the center Q of gripping by the quantity of displacement of the center of gravity of the parameter I (inertia moment), the kinetic energy is increased by a quantity Δa+ω even though the angular velocity ω does not change. Moreover, consequent upon approach of the center of gravity C towards the batting centroid Pc, it has been dynamically ascertained that the kinetic energy acting on the center of gravity C is so apt to be affected by the sweet spot that the kinetic energy applied to the ball then hitting the sweet spot may be assuredly increased.

On the other hand, the barrel portion B extends through the throat portion T to the grip portion G, over the grip end the non-circular sectional shape, for example, the oval sectional shape is represented and an inclination angle α is formed in a grip surface on an outer side relative to the longitudinal axis of the bat. The locking portion R of the oval sectional shape render the left hand of the right-handed batter to grip with its little finger side to the thumb side inclined and with the left-hand wrist being locked having been urged counterclockwise to thereby suppress the return of the back of the left hand during the bat swinging and also to suppress the bending of the left hand elbow during the impact. This leads to the action of “swinging the bat as if hitting with the grip” and brings about such a result as to increase the angular velocity of swinging of the bat. The angle of inclination α relative to a center line of a flared portion F is preferably increased with increase of the weight ΔM of the bat head. That is because, as the center of gravity displace towards the bat tip end, the back of the left hand during the bat swinging tends to return with the inertia force acting thereon.

As discussed above, when the right handed batter swings the bat accompanied by the rotation of the batter's physical body without returning the left hand palm and then hits the ball with the left arm elbow straightened steadily, the action “to swing the bat as if hitting the grip of the bat” can be accomplished and the maximum angular velocity that can be achieved by such batter can be exhibited. Also, although it has hitherto been suggested to initiate the swinging at an early state in order to hit the inside pitch, to hit the ball close to the pitcher and to delay the start of swinging so that the outside pitch can be hit, it is quite difficult since the timing of start of the batting is not the same. However, if the bat of the structure according to the present invention, the action “to swing the bat as if hitting the grip” can be accomplished and, therefore, the swinging can be simply accomplished with the impact point aligned in a line regardless of the tight, middle and inside balls (FIG. 13C).

The grip portion of the bat referred to hereinabove is such that the shape thereof varies from oval to circular from the grip end towards the grip center, and, although in the case of the oval shape the inclined portion is formed in the upper peripheral edge, if from the upper peripheral edge down to the lower portion of the grip end the side surface is flat with no step formed therein, the little finger side of the bottom hand is apt to slip since the end is nor raised up. In view of this, in the practice of the second preferred embodiment of the present invention, it is recommended to employ any one of the various grip structures shown and described in connection with the previously described first embodiment of the present invention. In particular, if the grip portion G of the bat is of the structure in which 1)′ when the bat grip portion G is 1)′ in which the palm of the bottom hand is brought into contact with a portion of the grip portion G which ranges from the grip end to the bat throat portion T, another portion of the grip portion ranging from the palm of the bottom hand to the middle finger of the upper hand represents a generally oval shape of which sectional surface perpendicular to the longitudinal axis of the bat is suited for the palmar grip and, in a direction upwardly over the middle finger of the upper grip a double stepped grip is formed in which the circular sectional surface of the bat throat portion is changed from the grip portion oval sectional shape; moving the grip center Gc to Gc1, selection of one of a finger grip and a half palmar grip in which, while the palmar grip for the bottom hand is secured, the little finger and the thumb finger in the grip is released, is possible, the batting centroid Pc is preferably adjustable to Pc1 and, yet, at least the intermediate portion of the semiperimetric portion of the grip portion that is gripped by the bottom hand and the upper hand and in the vicinity thereof 3) the region required to increase the coefficient of friction of the grip is preferably formed to reinforce the palmar grip.

According to the present invention hereinabove fully described, the kinetic energy F at the sweet spot during the bat swinging can be increased and the swinging can be corrected so that the maximum angular velocity can be attained during the bat swinging. Therefore, by the cumulative effects thereof, the maximum batting efficiency can be attained.

In any event, while the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings which are used only for the purpose of illustration, those skilled in the art will readily conceive numerous changes and modifications within the framework of obviousness upon the reading of the specification herein presented of the present invention. Accordingly, such changes and modifications are, unless they depart from the scope of the present invention as delivered from the claims annexed hereto, to be construed as included therein. 

What is claimed is:
 1. A bat structure which includes a bat head (H), a bat barrel portion (B), a bat throat portion (T), a bat grip portion (G) and a grip end (E), and the bat whole length is less than 86 cm according to the rule and the length of the bat grip portion is 25 to 35% of the bat whole length wherein; 1) the grip portion (G) comprises 3 parts extending from the grip end (E) to the bat throat portion (T) and a first part close to the grip end (E) has about half length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally vertical oval shape all over suited for gripping with palms of a bottom hand and a upper hand, a second part has less than one sixth length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is gradually changed from a generally vertical oval shape to a generally circle shape suited for gripping with thumb and index fingers of the upper hand and a third part close to the throat portion (T) has a remaining length of the grip portion and a sectional shape perpendicular to a longitudinal axis of the bat, which shape is represented by a generally circle shape.
 2. The bat structure as claimed in claim 1, in which the bat whole length for adult can be chosen from 82 cm to 86 cm while the bat whole length for boy can be chosen from 68 cm to 80 cm, and the length of the first part in the grip portion (G) is set from 11 cm to 14.5 cm.
 3. The bat structure as claimed in claim 1, characterized in that: 2) the grip end (E) is inclined forwards at an angle within a range of 20 to 30 degrees relative to a plane perpendicular to the longitudinal axis of the bat, and has a lock structure capable of turning about the hand wrist of the bottom hand to urge towards a thumb side.
 4. The bat structure as claimed in claim 1, characterized in that: 3) the grip end includes a top side, a bottom side which being opposite to the top side, a first right side and a second left side being opposite to the first right side, and projects laterally outwardly at the first right side or the second left side of an end inclined face over the generally oval section of the grip portion to form a bulge portion having a step portion between the grip end and the grip portion (G) for engaging with the little finger tip or the palm edge adjacent to the little finger third joint of the bottom hand in a manner to prevent the bottom hand edge from slipping out from the grp end during the swinging,
 5. The bat structure as claimed in claim 1, characterized in that: 4) a weight of the bat head H can be increased by adding a weight ΔM (10˜100 gr) to move the gravity center (C) of the bat from the original position toward the batting centroids Pc. 